%A LU Kun-Li,YIN Yan-Ping,WANG Zhen-Lin*,LI Yong,PENG Dian-Liang,YANG Wei-Bing,CUI Zheng-Yong,YANG Dong-Qing,JIANG Wen-Wen %T Effect of Nitrogen Fertilization Timing on Lignin Synthesis of Stem and Physiological Mechanism of Lodging Resistance in Wheat  %0 Journal Article %D 2014 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2014.01686 %P 1686-1694 %V 40 %N 09 %U {https://zwxb.chinacrops.org/CN/abstract/article_5731.shtml} %8 2014-09-12 %X

For understanding the effects of nitrogen management on lignin synthesis in wheat stem and plant lodging resistance, a field experiment was conducted, using the lodging resistant cultivar Jimai 22 and the lodging sensitive cultivar Shannong 16, in 2011–2012 and 2012–2013 growing seasons. The lignin accumulation in stem, activities of enzymes related to lignin synthesis, lodging resistance index, and grain yield were evaluated under four nitrogen treatments. All treatments received 240 kg ha–1 nitrogen during the whole growth period, in which 80 kg ha−1 was applied before sowing. The remaining nitrogen was applied at pseudo stem erection and booting stages (1:1) for N1, at jointing stage for N2, at jointing and anthesis stages (1:1) for N3, and at booting stage for N4 treatment. Compared with N2 and N3, N1 and N4 were superior in lignin content, stem mechanical strength, and lodging resistance. Nitrogen fertilization timing had significant effects on activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), and peroxidase (POD). Under N1 condition, the three key enzymes were in high activity. PAL, TAL and POD activities were higher in N2 treatment than in other treatments at 0–7 d after emergence of the second internode (ESI), and dropped rapidly at 21 d after ESI. Under N3 condition, the PAL, TAL and POD activities were low at 0–21 d after ESI, and the activity decline was alleviated by the nitrogen supplement at anthesis stage (21 d after ESI). Under N4 condition, the activities of these enzymes were increased after 14 d of ESI. At milk and dough stages, both cultivars had higher snapping resistance of the basal stem in N1 and N4 than in N2 and N3 treatments. Besides, the lodging resistance index and grain yield were also significantly higher in N1 and N4 than in N2 and N3. These results indicated that nitrogen applied at booting stage (N1 and N4 treatments) is propitious to increase PAL, TAL, POD activities and lignin content in stem, leading to the improved stem mechanical strength and decreased lodging area and lodging degree of wheat.